1. Field of the Invention
The present invention relates to a telephone system with a message recording function in a network such as an integrated services digital network (ISDN),in which a called party receives an incoming call together with a calling party identification data, which system records a voice message from the calling party received in the absence of the called party, in a voice mail recorder which reproduces the recorded message as the called party demands, and more particularly a system which facilitates the identification of the calling party of the voice message recorded in the voice mail recorder.
2. Description of the Related Art
A typical electronic private branch exchange is arranged so that a called party can set a voice mail recorder for the purpose of coping with such a situation that the called party receives an incoming call from a central office line during his absence, for example, in the nighttime.
In an automatic answering telephone system, when the user of the telephone set leaves home, the user can temporarily set a voice mail recorder to receive a message from a calling party during his absence.
The voice mail recorder records a voice message from a calling party directed to an absent called party and reproduces the recorded voice message through a telephone set when the called party gives a reproduction request to the recorder through the telephone set.
Most telephone systems equipped with such a voice mail recorder include a response device for sending a response message (voice message) to the calling party upon the reception of the incoming signal during the absence of the called party to ask the calling party whether he wants to leave a message, and in case he wants to do so, requests him to send calling party message. The response device comprises, for example, a voice ROM for storing voice data corresponding to the response message and a voice composer for reading out the recorded voice data and sounding it as a voice signal. The response device, when receiving the calling party voice message from the calling party responsive to the response message, causes the calling party voice message to be recorded in the voice mail recorder. In a telephone system including a plurality of telephone sets as extension-line terminals, a relay board and a voice mail recorder which are exchanged under control of a private branch exchange, when a called party is absent but an operator in charge of the relay board is present, the operator of the relay board can carry out such processing as asking the calling party whether he wants to leave message to the called party and if he desires so, setting the voice mail recorder as its message receiver and letting the calling party send the message.
Such a voice mail recorder usually has a memory area called memory box for recording the voice message. The memory box is divided into a plurality of blocks each having box number. The blocks are controlled on the basis of the respective box numbers. Each block is further divided into a plurality of subareas for storing one voice message. Accordingly, the time length of one voice message is determined by the capacity of the subarea. In the telephone system having a private branch exchange, the box numbers are usually assigned corresponding to the extension line numbers of these telephone sets.
Explanation will be made as to how to use the voice mail recorder on the assumption that the voice mail recorder is employed in a telephone system having an electronic private branch exchange.
Supposing that a called party is an extension line B and when a call is received from a calling party A through a central office line to the voice mail recorder during nighttime and the calling party A wishes to leave a message to the called party (the extension line B), then the calling party A informs the voice mail recorder by means of a dual-tone multifrequency tone of a box number corresponding to the extension line B together with a proper code (special number) indicative of a box number input. Then in response to the above-mentioned response message (or according to his or her guide message in the case where an operator is in charge of the relay board), the calling party A sends a desired message directed to the extension line (called party) B in a predetermined time. The voice mail recorder, when receiving the box number, retrieves non-recorded message one of the subareas of the block corresponding to the received box number and records the message sent from the calling party A in the retrieved subarea, which recording operation is completed after passage of a predetermined constant time.
Meanwhile, when the called party of the extension line B wishes to extract the message directed to his own extension from the voice mail recorder, the called party B acts as follows.
That is, the called party B dials an extension line number (extension line directory number of the voice mail recorder) allocated to the voice mail recorder on the telephone set assigned to the extension line B. When the voice mail recorder responds to this dialing operation, the called party B further dials the box number (which is often used together with a password) corresponding, e.g., to the extension line B to ask his own message. Responsive to it, the voice mail recorder retrieves the memory subarea corresponding to the dialed box number, reads out the recorded message of the calling party A therefrom and sends it to the extension line B. In this way, the called party can receive the message of the calling party A sent during his absence.
The called party B can know the presence or absence of a message arrival directed to the user of the extension line B, by means of:
A message registration indication on a display part of the associated telephone set or by means of a specific lamp previously allocated therefor.
Message retrieving operation of the voice mail recorder through the associated telephone set.
In such a prior art telephone system, the above registration of the voice message can be realized even when the calling party A already knows a key telephone number of such an organization having the above private branch exchange as a company or an office but he does not know the box number of the party as a called party.
With the prior art telephone system, the memory area for exclusively registering a message having an unknown box number is usually previously prepared in the voice mail recorder, that is, the received message having the not-specified box number is automatically recorded in the previously-prepared exclusive area of the voice mail recorder. Later, the operator in charge of the relay board can listen to the message of the unknown box number recorded in the exclusive area, confirm the extension line B of the called party on the basis of the listened destination and contents, and then inform the message contents of the corresponding party, e.g., the extension line B. Even in this case, if the operator is present and in charge of the relay board at the time of receiving the incoming signal, then the operator can assign the corresponding box number of the specified called party, i.e., the user of the extension line B to the message and then can register the message having the specified box number.
In any case, the user of the extension line B having received the message budges the calling party from the contents of the received message, and calls back to the calling party if necessary by checking the telephone number of the calling party.
With such a telephone system which can record a message received from a calling party in the voice mail recorder and can vocally reproduce the message recorded in the voice mail recorder in response to a reproduction request by a called party or by such an operator as a person in charge of the relay board, the message from the calling party can be left in the form of a voice message even when the called party is absent as in nighttime, whereby the telephone system can be reliably, simply and efficiently utilized in nighttime or as an automatic answering telephone system.
However, in this telephone system, all the message data from the calling party, i.e., the telephone number, name and so on of the calling party are all obtained from this voice message, so that, if the calling party fails to leave such a calling party identification data as his own telephone number in the form of a voice message, then it is difficult for the called party to immediately specify the calling party's telephone number even on the basis of the received message. That is, even when the called party wishes to call back to the calling party, the called party must check the calling party's telephone number every time the called party does not know it by heart.
The prior art telephone system has another problem that, since the voice message recorded and registered in its exclusive area in the voice mail recorder as a message having an unknown box number is informed from the operator of the relay board to the corresponding called party as explained above, the contents of the message might not be able to be sufficiently transmitted to the called party. In addition, such a message that requires its confidentiality between the calling party and the called party cannot be left in such a voice mail recorder.
Furthermore, even when the calling party himself or the operator in charge of the relay board assigns a box number corresponding to the called party, this operation is highly troublesome from the viewpoint of its manual handling operation.